<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        // let arr = new Array;
        // arr = [1, 2, 3];
        // arr[3] = "kk";
        // console.log(typeof arr);
        // console.log(arr);
        // arr.splice(2, 1);
        // console.log(arr);


        // function hellow() {
        //     console.log("hellow");

        // }
        // hellow();
        // function add(x, y) {
        //     let sum = x + y;
        //     console.log("x+y" + "=" + sum);
        //     return sum;
        // }
        // add(7, 9);
        // let sum = function (x, y) {
        //     return x + y;
        // }
        // console.log(typeof sum);

        //对象
        let obj = {};//空
        let stu = {
            "id": 1,
            "name": "zhangsan",
            "class": "java",
            "age": 18

        }
        stu.gender = "nan";
        console.log(stu);

    </script>
</body>

</html>